1. Field of the Invention
The invention relates to the recycling of waste oil. More particularly, the invention relates to a method and apparatus for filtering engine lubrication waste oil and blending it with diesel fuel to produce a water free diesel fuel that can be burned in a diesel engine or other fuel oil consuming device.
2. State of the Art
Recycling of waste materials has been and continues to be a matter of great national concern. Moreover, conservation of petroleum products has been and continues to be a matter of equal national concern. Presently, internal combustion engines are widely used throughout the United States and throughout the world. Virtually all of these engines, in addition to consuming petroleum products during combustion, use lubrication oil which is not consumed, but which is contaminated through use. The lubrication oil in an internal combustion engine must be replaced quite frequently, and the disposition of the used lubrication oil is a continuing environmental problem.
As early as 1975, methods were proposed for the large scale removal of lead and other suspended solids from used hydrocarbon lubrication oil. One such method is described in U.S. Pat. No. 3,923,643 to Lewis et al. where the used lubrication oil is subjected to heat treatment and centrifuging or gravity settling. The purified oil may be suitably employed in many industrial applications of heavy oils such as fuel oil.
On a very small scale (i.e. within an individual engine) it has been known to blend used lubrication oil with fuel oil as a means of conservation and as a method of disposing of the used lubrication oil. U.S. Pat. No. 4,421,078 to Hurner describes an apparatus for extracting small quantities of lubrication oil from the oil pan of a truck engine and blending the lubrication oil with fuel oil while the extracted oil is automatically replenished with fresh lubrication oil. Hurner does not treat the used lubrication oil before mixing it with fuel oil, however. A similar, though more elaborate system is disclosed in U.S. Pat. No. 4,345,429 to Yasuhara where engine lubrication oil is blended with engine fuel oil, but only after the lubrication oil has been atomized in a soot collector placed inline with engine exhaust gasses.
A method and apparatus for reclaiming contaminated oil on an intermediate scale is disclosed in U.S. Pat. No. 4,784,751 to McGehee. McGehee's apparatus includes a divided tank which is approximately 4'.times.4'.times.3' and mounted on wheels for use in a truck service station or similar facility. Contaminated oil is reclaimed for fuel use by pumping it through an oil filter into one side of a divided tank from which it is heated to bum off water and antifreeze, and then into the other side of the tank where the oil is blended with clean oil such as diesel fuel. The mixture is then pumped through a water separator and another oil filter.
In order to produce an efficient blend of fuel oil and recycled lubrication oil, a precise mixture of the two components is necessary. While it is generally known to blend recycled lubrication oil with new fuel oil, precision methods of performing such a blending on a large scale are not available. Moreover, it is also necessary that the recycled component be thoroughly filtered prior to blending with new fuel oil and that the blend be dehydrated. While some of the known methods produce a relatively clean recycled component, they do so at the expense of time which prohibits their application in a large scale operation.